hello @Aliz6 ! Welcome to our community!
At this moment it is not possible to export detections rules in other format, rather then .ndjson according to Export rules | Elastic Security Solution [8.7] | Elastic
But once rules exported, .ndjson can be converted into .csv with using third party tools.
I can't recommend any, as I never used any. But it looks like there are plenty of them.
There is also a similar question on the forum: Export rules into excel or CSV or PDF format
Note: to export pre-built rules, you can duplicate them and then export. See Manage detection rules | Elastic Security Solution [8.7] | Elastic
Hope this helps
Thank you, Vitalii